Request the resize of ShellSurface after Decoration updated the borders when maximizing

Summary:
This ensures that we don't send a size request with the borders still
added.

Test Plan:
Verified that a maximized window is properly sized and
doesn't have empty borders

Reviewers: KWin, Plasma on Wayland

Subscribers: plasma-devel, kwin

Tags: Plasma on Wayland, KWin

Differential Revision: https://phabricator.kde.org/D1807